/*
 * Copyright 2002-2012 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.hotswap.agent.util.spring.io.loader;

import org.hotswap.agent.util.spring.io.resource.ClassPathResource;
import org.hotswap.agent.util.spring.io.resource.ContextResource;
import org.hotswap.agent.util.spring.io.resource.Resource;
//import org.springframework.util.Assert;
//import org.springframework.util.StringUtils;
import org.hotswap.agent.util.spring.util.Assert;
import org.hotswap.agent.util.spring.util.StringUtils;

/**
 * {@link ResourceLoader} implementation that interprets plain resource paths as
 * relative to a given {@code java.lang.Class}.
 *
 * @author Juergen Hoeller
 * @since 3.0
 * @see Class#getResource(String)
 * @see ClassPathResource#ClassPathResource(String, Class)
 */
public class ClassRelativeResourceLoader extends DefaultResourceLoader {

    private final Class<?> clazz;

    /**
     * Create a new ClassRelativeResourceLoader for the given class.
     * 
     * @param clazz
     *            the class to load resources through
     */
    public ClassRelativeResourceLoader(Class<?> clazz) {
        Assert.notNull(clazz, "Class must not be null");
        this.clazz = clazz;
        setClassLoader(clazz.getClassLoader());
    }

    @Override
    protected Resource getResourceByPath(String path) {
        return new ClassRelativeContextResource(path, this.clazz);
    }

    /**
     * ClassPathResource that explicitly expresses a context-relative path
     * through implementing the ContextResource interface.
     */
    private static class ClassRelativeContextResource extends ClassPathResource implements ContextResource {

        private final Class<?> clazz;

        public ClassRelativeContextResource(String path, Class<?> clazz) {
            super(path, clazz);
            this.clazz = clazz;
        }

        @Override
        public String getPathWithinContext() {
            return getPath();
        }

        @Override
        public Resource createRelative(String relativePath) {
            String pathToUse = StringUtils.applyRelativePath(getPath(), relativePath);
            return new ClassRelativeContextResource(pathToUse, this.clazz);
        }
    }

}